1. Field of the Invention
The present invention relates to processing of digital images. More particularly, the present invention relates to methods for adjusting digital camera image processing parameters in order to achieve improved performance of a digital camera image processing pipeline.
2. The Prior Art
It is quite common that the main camera image processing parameters, particularly, those used to control the noise reduction process, are linked to the ISO sensitivity setting. The quality of images taken at various ISO settings depends greatly on the quality of the algorithm used for noise reduction.
Since noise increases with the increase of ISO sensitivity, as usually demonstrated in terms of the signal-to-noise ratio measurements, it is often necessary to use more aggressive noise reduction at higher ISO sensitivities. However, since aggressive noise reduction smoothes out fine details and blurs the edges in the image, it is also possible to leave more noise in the processed images taken at high ISO settings compared to the processed images taken at low ISO settings.
Unfortunately, the ISO setting is a global parameter which does not address the problem of excessive highlights, deep shadows, and uneven illumination in the scene, and also does not account for overexposure and underexposure effects introduced through the automatic camera capture process or by the user. To avoid this problem, a different solution is needed.